The present invention relates to window hardware and more particularly to window sash lock hardware and still more particularly to window sash lock keepers.
Common window sash and rail materials include extruded polymer rails having intricate cross sections, which are designed to accept weather striping, glass and internal reinforcement members. Typical window sash extrusions comprise an exterior surface having slots or protrusions which mate with slots or protrusions in a complementary window rail extrusion when the complementary extrusions are placed in mating proximity to each other, for example by closing a window.
It is well known to employ a manual window sash lock in combination with a keeper to secure a window in a closed position. A moveable locking arm mechanism is typically mounted to a first window extrusion by mechanical fasteners, typically screws, and a keeper is typically mounted to a mating second window extrusion by mechanical fasteners, typically screws, so that the moveable locking arm is positioned to capture the keeper when the window is closed.
It is known that a first window extrusion having a sash lock mounted thereto must be closely aligned to a second window extrusion having a keeper mounted thereto in order for the sash lock to properly capture the keeper. Sash locks and keepers are designed with close clearances to prevent even small relative movements therebetween so that windows are tightly secured when a lock arm engages a keeper. Even small misalignments between a sash lock and a keeper may cause a mechanical interference, which prevents proper motion of a lock arm or proper closing of a window.
It is known that segments of protrusions, which extend from window sash and rail extrusions, are typically cut away in order to provide a flat surface to which a window sash lock keeper may be installed. Corresponding segments of protrusions, which extend from the mating extrusion, are typically cut away to provide clearance for a sash lock keeper when a window is closed. Often machining or cutting operations used to remove protrusions from an extrusion leave a residual protrusion of material or burr on the extrusion surface. Typical sash lock keepers that are mounted to an extrusion surface having a residual protrusion or burr are prevented by the residual protrusion or burr from properly abutting the extrusion surface. Sash lock keepers are often thereby misaligned and cause potential interference with sash lock hardware or a mating extrusion.